CN114759959B - Phased array beam forming method for inhibiting interference between beams - Google Patents
Phased array beam forming method for inhibiting interference between beams Download PDFInfo
- Publication number
- CN114759959B CN114759959B CN202210381030.6A CN202210381030A CN114759959B CN 114759959 B CN114759959 B CN 114759959B CN 202210381030 A CN202210381030 A CN 202210381030A CN 114759959 B CN114759959 B CN 114759959B
- Authority
- CN
- China
- Prior art keywords
- representing
- user
- interference
- main lobe
- base station
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 34
- 230000002401 inhibitory effect Effects 0.000 title abstract description 5
- 238000005457 optimization Methods 0.000 claims abstract description 56
- 238000004891 communication Methods 0.000 claims abstract description 18
- 239000013598 vector Substances 0.000 claims description 31
- 238000005070 sampling Methods 0.000 claims description 22
- 230000005540 biological transmission Effects 0.000 claims description 17
- 230000008054 signal transmission Effects 0.000 claims description 9
- 239000000654 additive Substances 0.000 claims description 3
- 230000000996 additive effect Effects 0.000 claims description 3
- 238000013461 design Methods 0.000 abstract description 17
- 230000001629 suppression Effects 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 2
- 230000005764 inhibitory process Effects 0.000 abstract 1
- 239000011159 matrix material Substances 0.000 description 18
- 238000004088 simulation Methods 0.000 description 5
- 238000000342 Monte Carlo simulation Methods 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- BJRNKVDFDLYUGJ-RMPHRYRLSA-N hydroquinone O-beta-D-glucopyranoside Chemical compound O[C@@H]1[C@@H](O)[C@H](O)[C@@H](CO)O[C@H]1OC1=CC=C(O)C=C1 BJRNKVDFDLYUGJ-RMPHRYRLSA-N 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0426—Power distribution
- H04B7/043—Power distribution using best eigenmode, e.g. beam forming or beam steering
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/391—Modelling the propagation channel
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
- H04W24/02—Arrangements for optimising operational condition
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
The invention discloses a phased array beam forming method for inhibiting interference among beams, which takes the linear combination of the power of the minimum beam in the interference direction and the power of the beam in the central area of a main lobe as an optimization target by introducing a weight factor under the condition of meeting the constant mode constraint of a phased array, and optimally designs single or multiple beams by means of a manifold optimization tool box. In the millimeter wave multiuser communication system, the invention can achieve the average and rate performance of approximate mixed beam forming under the condition of using only analog beam forming and not using digital beam forming, and has effective inhibition effect on interference among users. In a radar system, the phased array beam forming method provided by the invention has better interference suppression performance compared with the existing method.
Description
Technical Field
The invention relates to the technical field of phased array beamforming for inhibiting inter-beam interference, in particular to a phased array beamforming method for inhibiting inter-beam interference.
Background
With the development of wireless communication in recent years, wireless telephone service has been continuously upgraded, and mobile communication systems face explosive data traffic growth and mass device connection, which stimulates research on application of millimeter waves to wireless communication. The millimeter wave has short wavelength, which is only a few millimeters, so that millimeter wave communication can be performed under the condition of smaller antenna size, a transceiver can be configured with a large-scale antenna array in a limited area, and the millimeter wave system mainly utilizes the large-scale antenna array to form wave beams to realize high-speed transmission. However, due to the existence of a large number of antennas, it is difficult to implement the dedicated radio frequency link allocated to each antenna in terms of hardware, and high power consumption and high radio frequency link cost are also caused, so that a hybrid architecture using a small number of radio frequency links to drive all antenna array elements through a certain number of phase shifters is widely applied in the existing millimeter wave system.
In a millimeter wave multi-user wireless communication system, different data streams can occupy the same time-frequency resource, and different data are transmitted by forming beams through space division multiplexing. In practical engineering, mutual interference occurs between different data streams. The phased array network formed by the phase shifters is required to design the wave beam for transmitting data under the constraint of the number of radio frequency chains so as to achieve the aim of suppressing the interference among data streams. However, since the phase shifter is only adjustable in phase, each element in the phased array has a constraint of a constant modulus value, so how to perform beamforming design for suppressing inter-beam interference on the phased array is a difficulty of the millimeter wave multi-user wireless communication system.
Furthermore, in radar systems, it is often desirable to suppress interference of clutter and other signals by minimizing the power of signals transmitted to and received from noise sources, and therefore, interference suppression designs of beams are of great importance to improve the performance of radar systems. The formation of nulls in specific directions of beam patterns is an effective anti-interference technique in radar systems, and pure phased array networks are of great interest in large phased array systems because of the economics and simplicity of their feed networks, and how to design beams so that nulls are formed in specific directions to achieve interference suppression is also a difficulty in radar systems with constant module value constraints.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a phased array beam forming method for suppressing interference between beams, which optimizes and designs a single or multiple beams by means of a manifold optimization tool box by introducing a weight factor to minimize a linear combination of power of the beam in an interference direction and power of the beam in a central area of a main lobe under the condition of satisfying a constant modulus constraint of a phased array.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a phased array beamforming method of suppressing inter-beam interference, the method comprising the steps of:
step S1, aiming at a wireless system, constructing an optimization problem with the linear combination of the power of the minimized wave beam in the interference direction and the power of the wave beam in the central area of the main lobe as an optimization target; the wireless system comprises a millimeter wave multiuser wireless communication system and a radar system, and the optimization problem satisfies the constant mode constraint of all phase shifters in the phased array;
step S2, single or multiple beams are designed for the wireless system by solving the optimization problem constructed in the step S1.
Further, in the step S1, when the wireless system is a millimeter wave multi-user wireless communication system, a downlink signal transmission model is first constructed to minimize a linear combination of the power of the current user beam in the main lobe center area and the power of the beam in the main lobe center areas of the other user beams, so as to construct an optimization problem as an optimization target.
Further, in the step S1, if the base station can obtain the accurate departure angle of each user, the main lobe center area is simplified to be a center point.
Further, the downlink signal transmission model specifically represents:
wherein y is q A signal representing the user's receipt;representing the downlink channel vector between the base station and the qth user, for example>Representing the complex field, (. Cndot. H Representing a conjugate transpose operation; />K column vectors +.>A beamforming vector representing the transmission of the base station to K users; />Representing data flows sent by a base station to K users, which satisfyPower constraint, P s The q-th element s representing the transmission power of the base station s] q Representing data sent by a base station to a qth user；η q Representing the additive white noise received by the qth user, subject to a mean of 0 and a variance of sigma 2 Is a complex gaussian distribution of (c).
Further, in the downlink signal transmission model, the channel modeling is as follows:
wherein N is t Indicating the number of base station antennas L q Representing the total number of multipaths, alpha, of the channel between the base station and the qth user q,l And phi q,l The complex gain and departure angle of the first path of the q-th user are respectively represented; a (phi) q,l ) An array steering vector representing the first path of the qth user, the specific expression of which is:
wherein lambda is c For carrier wavelength, d represents the antenna element spacing, (·) T Representing a transpose operation.
Further, the optimization problem is specifically expressed as:
wherein λ is a positive real weight factor, θ k,j A J-th sampling point, k=1, 2, …, K, j=1, 2, …, J, representing the central region of the main lobe of the kth beam; w (w) q Represents F RF Is the q-th column of (2);the power sum of the sampling points of the q-th beam in the central area of the main lobe of other beams is defined as the interference power sum of the q-th beam to the other beams; m represents the number of sampling points in the center region of the main lobe of the qth beam, +.>Representing the sum of the powers of the M sampling points of the q-th beam in the central area of the main lobe of the q-th beam; i·| represents modulo value, [ w ] q ] n Representing beamforming vector w q According to the constant modulus constraint of all phase shifters of the phased array, w q Each element of (a) satisfies
Further, when the base station can obtain the accurate departure angle of each user, the main lobe central area is simplified to be a central point, and the corresponding optimization problem is specifically expressed as:
wherein θ k Representing the main lobe center point of the kth beam.
Further, when the wireless system is a radar system, an optimization problem is constructed for an optimization objective with a linear combination of minimizing the power of the beam in the center region of its main lobe and the power of the beam in the interference region.
Further, when the wireless system is a radar system, the optimization problem is specifically expressed as:
wherein λ is a positive real weight factor, w represents a beamforming vector, θ i,j Representing the jth sample point in the ith interference region,representing the sum of the powers of the beams at the sampling points of the interference area; m represents the number of sampling points in the central region of the main lobe of the beam,/->Representing the sum of the powers of the M sampling points of the beam in the central region of the main lobe of the beam; [ w ]] n An nth element representing a beamforming vector w, each element in w satisfying +.>
Further, in the step S2, the optimization problem is solved by a manifold optimization tool box.
The beneficial effects of the invention are as follows:
1. for the millimeter wave multiuser beam forming problem under the full connection architecture, the invention establishes an optimization problem model by considering the interference suppression among beams emitted to different users by a base station, and based on the optimization problem model, a beam forming method is provided, and the method can achieve the average and rate performance similar to the hybrid beam forming under the condition that only analog beam forming is used instead of digital beam forming;
2. for the problem of phase-only beam design to suppress interference in radar systems, the invention provides an effective beam design scheme which has better performance than the existing phase-only beam null design scheme.
Drawings
Fig. 1 and 2 are schematic diagrams of a millimeter wave multiuser wireless communication system model used in embodiment 1 of the invention;
fig. 3 is a graph comparing the average user sum rate and the average user sum rate of the mixed beam forming and the full digital beam forming of the beam forming method provided by the embodiment 1 of the invention when the base station is provided with 64 array elements, the array element interval is half wavelength, the number of radio frequency links is 4, the base station obtains an accurate departure angle, and the total number of transmission paths between the user and the base station is equal to 1;
fig. 4 is a graph comparing the average user sum rate of the beam forming method designed under the condition of inaccurate departure angle with the average user sum rate of the hybrid beam forming and all-digital beam forming designed under the condition of accurate departure angle by utilizing the embodiment 1 of the invention when the base station is provided with 64 array elements, the array element interval is half wavelength, the number of radio frequency links is 4, and the total number of transmission paths between the user and the base station is equal to 1;
fig. 5 is a graph comparing the average user sum rate of the beam forming method designed under the condition of inaccurate departure angle with the average user sum rate of the hybrid beam forming and all-digital beam forming designed under the condition of accurate departure angle by utilizing the embodiment 1 of the invention when the base station is provided with 64 array elements, the array element interval is half wavelength, the number of radio frequency links is 4, and the total number of transmission paths between the user and the base station is equal to 3;
fig. 6 is a comparison of a beam designed by example 2 of the present invention and a beam designed by the semi-fixed relaxation algorithm in document [1] and the kronecker decomposition algorithm in document [2] when the radar antenna array is provided with 32 array elements and the array element interval is half wavelength.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
Referring to fig. 1-5, the present embodiment provides a phased array beam method for suppressing inter-beam interference in a millimeter wave multi-user wireless communication system, which specifically includes the following steps:
step S1, constructing a millimeter wave-based multiuser wireless communication system model, wherein the structure of the model is shown in FIG. 1, and specifically:
aiming at a downlink communication scene that a base station serves K users, the users are all single-antenna users, the base station adopts a fully-connected hybrid wave beam forming architecture, and the number of radio frequency links is equal to the number of users, namely N RF =k, antenna arrayIs arranged as N t The root antenna and the antenna are spaced into a uniform linear array with half wavelength.
Specifically, taking the q-th user as an example, the downlink signal transmission model can be established as follows:
wherein y is q A signal representing the user's receipt;representing the downlink channel vector between the base station and the qth user, for example>Representing a complex field; />Representing the data streams sent by the base station to K users, which satisfy +.>Power constraint, P s The q-th element s representing the transmission power of the base station s] q Data representing the transmission of the base station to the qth user; η (eta) q Representing the additive white noise received by the qth user, subject to a mean of 0, and a variance of sigma 2 Is of complex Gaussian distribution, i.e.)>Analog beamforming matrix representing a base station, analog beamforming being performed on a phased array network of phase shifters constrained by constant modulus values of the phase shifters, i.e. F RF Each element of (2) satisfies +.> Digital beam representing a base stationForming a matrix.
Specifically, in the present embodiment, the beamforming method adopted is phased array beamforming without using digital beamforming, and therefore the digital beamforming matrix is set as an identity matrix, i.e., F BB ＝I K The hybrid beamforming architecture in fig. 1 is simplified to the analog beamforming architecture in fig. 2, and the above downlink signal transmission model is simplified to:
wherein F is RF K column vectors of (2)Respectively representing the beamforming vectors sent by the base station to K users.
Specifically, in this embodiment, in the downlink signal transmission model, the channel modeling is as follows:
wherein L is q Representing the total number of multipaths, alpha, of the channel between the base station and the qth user q,l And phi q,l The complex gain and departure angle (Angle of Departure, AOD) of the first path of the qth user are shown, respectively. a (phi) q,l ) An array steering vector representing the first path of the qth user, the specific expression of which is:
wherein lambda is c For carrier wavelength, d represents the antenna element spacing, (·) T Representing a transpose operation.
Step S2, establishing a beam forming model which has constant mode constraint and suppresses the interference among beams aiming at the millimeter wave-based multi-user wireless communication system model constructed in the step S1;
in particular, since the users are single-antenna single-radio-frequency-chain users, the beam forming matrix F is simulated to maximize the signal power received by the users RF The main lobe centers of the K beams formed need to be aligned with the AODs of paths (typically line-of-sight paths) with the maximum complex gain of the K users, respectively, denoted asHowever, due to the presence of side lobes, interference inevitably exists between beams, affecting communication between the base station and the user.
Step S201, according to whether the base station can obtain the accuracy of each userTo build different optimization problems if the base station cannot obtain an exact +_ for each user>An optimization problem is constructed for the optimization objective with a linear combination that minimizes the power of the current user beam in its main lobe center region and the power of that beam in the remaining user beam main lobe center regions.
Specifically, in the present embodiment, the step S201 includes:
to reduce the influence of inter-beam interference on the communication quality, it is necessary to suppress the inter-beam interference. Furthermore, it is considered that the base station may not acquire the accuracy of each user due to the influence of the beam resolution in the beam scanning stageBut only get +.>An angular domain range Ω with a width of beam resolution k There is a pair->Positioning errors, i.e. beam scanning errors, so base stationsThe beam center is aligned with the angular domain range omega when actually transmitting the beam k Center of (2), not exactly +.>Accurate->May be distributed in omega k Any position of (3). Thus, in order to suppress interference between beams transmitted to different users while ensuring communication quality for each user, it is necessary to make a single beam at Ω of the remaining beams with as small a main lobe shift as possible k The region forms a null. The design problem of the beams of the multiple users is K sub-problems independent of each other.
More specifically, in the present embodiment, taking the design of the beam to be transmitted to the qth user as an example, the beamforming vector w q ＝F RF The design problem of (: q) can be established as an optimization problem of beam area nulling:
wherein λ is a positive real weight factor, θ k,j A J-th sampling point, k=1, 2, …, K, j=1, 2, …, J, representing the central region of the main lobe of the kth beam; w (w) q Represents F RF Is the q-th column of (2);representing the allocation of the q-th user beam in the central region omega of the main lobe of the other user beams k The sum of the powers of the sampling points of (a), namely the sum of the interference power caused by the beam of the (q) th user to the beams of the other users; m represents the number of sampling points in the central region of the main lobe of the current beam to be designed, i.e., the q-th beam, +.>Representing the sum of the powers of the M sampling points of the q-th beam in the central area of the main lobe of the q-th beam; i·| represents modulo value, [ w ] q ] n Representing beamforming vector w q According to the constant modulus constraint of all phase shifters of the phased array, w q Each element of (2) satisfies +.>
Step S202, if the base station can obtain the accuracy of each userThen there is no need for a main lobe center region Ω for each beam k Sampling is performed, and the central area of the main lobe in the above optimization problem is simplified to be a central point, so the optimization problem of the beam area null constructed in step S201 may be simplified to be an optimization problem of the multipoint null, which is specifically expressed as:
wherein θ k Representing the main lobe center point of the kth beam.
Step S203, solving the above-constructed beam region null optimization problem or the multi-point null optimization problem, which includes: setting a weight factor lambda, and solving an optimization problem through a manifold optimization tool box to obtain a beam forming vector w q . Similarly, w can be sequentially solved k (1. Ltoreq.k. Ltoreq.K) and obtaining an analog beamforming matrix F RF Wherein F RF (:,k)＝w k 。
Example 2
Referring to fig. 6, the present embodiment provides a phased array beam design method for suppressing inter-beam interference of a radar system, which is based on a radar antenna array with half-wavelength array element interval, and the number of array elements is N t The arrays are arranged in a uniform linear array. The method specifically comprises the following steps:
step S1, determining the radar system, and constructing a beam pattern expression of the radar system, wherein the method specifically comprises the following steps:
step S101, for the uniform linear array, the array steering vector in the θ direction is expressed as:
in step S102, let the beamforming vector be w, the corresponding beam pattern may be expressed as:
f(θ)＝|w H a(θ)| 2
where || represents modulo.
Step S2, designing the beam pattern constructed in step S1, where the designing includes: and constructing an optimization problem by taking the linear combination of the minimized power of the beam in the central area of the main lobe and the power of the beam in the interference area as an optimization target, and solving the optimization problem to obtain a beam forming vector.
Specifically, in this embodiment, the step S2 specifically includes:
in step S201, in order to suppress interference in a specific direction, the beam needs to be designed so that the beam pattern forms nulls in the specific direction, which can be translated into minimizing the power allocated to the specific direction by the beam. Meanwhile, in order to reduce the shift of the main lobe as much as possible, it is also necessary to ensure that the power of the beam is maximized in the central region of the main lobe. The design problem of the beamforming vector w may be established as an optimization problem as follows:
wherein λ is a positive real weight factor, θ i,j Represents the value of i=1, 2, …, I,representing the sum of the powers of the beam at the sampling points of the interference area. M represents the number of sampling points in the central region of the main lobe of the beam,/->Representing the sum of the powers of the beam at M sample points in the central region of its main lobe. I·| represents modulo value, [ w ]] n An nth element representing a beamforming vector w, each element in w satisfying +.>
Step S202, a weight factor lambda is set, and the optimization problem is solved through a manifold optimization tool box to obtain a beam forming vector w.
In order to verify the correctness and advancement of the methods in the above-mentioned embodiment 1 and embodiment 2, simulation experiments were performed, specifically including:
the simulation parameters of fig. 3 are: base station antenna number N t Number of RF links N of 64 RF For 4, the base station serves k=4 total users. Total number of transmission paths L between user and base station k Equal to 1, contains only 1 main path, and the main path gain obeys complex Gaussian distribution, namelyThe channel state information of the base station is the accurate path AOD, and the weight factor λ=1000. In fig. 3, an optimization problem model is first established by step S202 in embodiment 1, and then a beamforming vector of each user is obtained through a manifold optimization tool box to form a simulated beamforming matrix. In combination with the actual channel, the transmission signal-to-noise ratio is changed, 2000 Monte Carlo simulations are performed, and a relation curve of the average sum rate of the users and the SNR is drawn, as shown by a circular solid line in FIG. 3. Meanwhile, a relationship between the average sum rate of users and the SNR under the mixed beamforming condition is drawn, as shown by an asterisk solid line in fig. 3, and a relationship between the average sum rate of users and the SNR under the all-digital beamforming condition is drawn, as shown by a dotted line in fig. 3. The expression of the user average sum rate is
Wherein R is k Representing the achievable rate of the kth user, expressed in particular as
Wherein f=f RF F BB It is noted that F of hybrid beamforming, all-digital beamforming and phased array beamforming proposed by the present invention is F respectively 2 、F 3 And F 1 . F for phased array beamforming 1 ＝F RF The method comprises the steps of carrying out a first treatment on the surface of the Hybrid beamforming, i.e. solid asterisksBy peer-to-peer effective channel matrix H eq ＝HF RF Zero-forcing precoding, i.e. F BB ＝(H eq ) -1 ＝(HF RF ) -1 Wherein H= [ H ] 1 ,h 2 ,…,h K ] H Preliminary hybrid beamforming matrix F HB ＝F RF F BB Since hybrid beamforming does not have power gain, it is also necessary to do so for F HB Performing energy normalization on each column to obtain final F 2 I.e. +.> All digital beamforming +.>For zero-forcing precoder, F 3 ＝H H (HH H ) -1 . Comparing the three curves, the beam forming method provided by the invention can achieve the same performance as the hybrid beam forming, and compared with the all-digital beam forming, the average sum rate of the two users is only different by 0.0457bps/Hz when the SNR is 15 dB. This is because the phased array wave proposed by the present inventionWhen the beam forming method designs the beam of the user, the energy distributed by the beam of the current user at the beam central position of other users is as close to zero as possible, and the equivalent channel matrix H eq ＝HF RF The modulus of the off-diagonal element is close to 0, and the task of inter-user interference suppression is completed, so that the same performance as that of hybrid beam forming can be achieved.
The simulation parameters of fig. 4 are: base station antenna number N t Number of RF links N of 64 RF For 4, the base station serves k=4 users altogether. Total number of transmission paths L between user and base station k The path gain of the main path obeys a complex gaussian distribution, equal to 1, i.eThe channel state information of the base station is an inaccurate path departure angle, and a weight factor lambda=1000. In fig. 4, an optimization problem model is first established by using step S201 in embodiment 1, and then a beamforming vector of each user is obtained through a manifold optimization tool box, so as to form a phased array beamforming matrix. In combination with the actual channel, the transmission signal-to-noise ratio is changed, 2000 monte carlo simulations are performed, and a curve of the average sum rate of the users and the SNR is drawn, as shown by a circular solid line in fig. 4. Meanwhile, a relationship between the average sum rate of users and the SNR under the mixed beamforming condition is drawn, as shown by an asterisk solid line in fig. 4, and a relationship between the average sum rate of users and the SNR under the all-digital beamforming condition is drawn, as shown by a dotted line in fig. 4. In order to indicate the performance upper bound, H used in calculating the hybrid beamforming matrix and the all-digital beamforming matrix is accurate channel state information, i.e., an accurate path departure angle. As can be seen by comparing the three curves, the beamforming method provided by the invention can be applied to SNR<The same performance as hybrid beamforming is achieved at 20dB and the user average sum rate of both differs by only 1.13bps/Hz at an SNR of 15dB compared to all-digital beamforming. This is because the phased array beam forming method provided by the invention designs the beams of the users so that the energy distributed by the current user beam in the central area of the beams of other users is as small as possible, and the equivalent channel matrix H eq ＝HF RF The approach to the diagonal matrix plays a role in interference suppression, so that the same performance as that of the hybrid beamforming can be achieved when SNR is small, i.e., noise is the main factor affecting the rate.
The simulation parameters of fig. 5 are: base station antenna number N t Number of RF links N of 64 RF For 4, the base station serves k=4 users altogether. Total number of transmission paths L between user and base station k Equal to 3, comprises 1 main path and 2 auxiliary paths, wherein the path gain of the main path is subject to complex Gaussian distribution, namelyThe path gain of the slave path also follows a complex Gaussian distribution and the energy is 1/100 of the main path, i.e.>The channel state information of the base station is an inaccurate path departure angle, and a weight factor lambda=1000. In fig. 5, an optimization problem model is first built by step S201 in embodiment 1, and a beamforming vector of each user is obtained by a manifold optimization tool box, so as to form a simulated beamforming matrix. In combination with the actual channel, the transmission signal-to-noise ratio is changed, 2000 monte carlo simulations are performed, and a curve of the average sum rate of the users and the SNR is drawn, as shown by a circular solid line in fig. 5. Meanwhile, a relationship between the average sum rate of users and the SNR under the mixed beamforming condition is drawn, as shown by an asterisk solid line in fig. 5, and a relationship between the average sum rate of users and the SNR under the all-digital beamforming condition is drawn, as shown by a dotted line in fig. 5. In order to indicate the performance upper bound, H used in calculating the hybrid beamforming matrix and the all-digital beamforming matrix is accurate channel state information, i.e., an accurate path departure angle. Comparing the three curves, it can be found that the performance of the phased array beam forming proposed by the invention is lower than that of the hybrid beam forming combined with zero-forcing precoding due to the interference of 2 paths, but can still be at SNR<The same performance as hybrid beamforming is achieved at 10 dB. This is because the phased array beam forming method provided by the invention enables the beam of the current user to be divided when the beam of the user is designedThe energy allocated to the central area of other user wave beams is as small as possible, thus playing the role of interference suppression.
The simulation parameters of fig. 6 are: number of antennas of radar uniform linear array N t =32, the array element spacing is half wavelength. Beam center angle θ 0 The main lobe central region corresponds to an interval of [ -1.7 °,1.7 °]The sampling point number m=5. The interference area, i.e. the null interval, is [ -10.8 DEG, -14.45 DEG °]∪[14.9°,18.2°]I=2, the number of samples per interference area is j=10, and the weight factor λ=5000. In fig. 6, an optimization problem model is first built by using step S201 in embodiment 2, the beamforming vector w is solved by the manifold optimization tool box, and the beam corresponding to w is drawn, as shown by the solid line in fig. 6. At the same time, draw document [1]]Beams designed by the semi-definite relaxation algorithm of (2)]The kronecker decomposition algorithm in (c) and the quasi-static beams without beam nulling, as shown by the dashed, dotted and dashed lines in fig. 6. As can be seen by comparing the 4 curves, in the null region, the array gain of the wave beam designed by the invention is below-60 dB and is lower than that of the document [1]]And literature [2]And about 40dB lower than the array gain peak of the quasi-static beam in that interval; in the beam center position, the beam designed by the invention has only 1.16dB drop in array gain compared with quasi-static beam, compared with document [1]]The array gain is only 0.26dB different from the designed beam, compared with document [2]]The array gain is 10.06dB higher than the designed beam. Therefore, the beam designed by the invention can obtain the optimal interference suppression performance on the premise of ensuring the array gain of the central area of the main lobe.
The above document [1] is: P.J. Kajenski.Phase Only Antenna Pattern Notching Via a Semidefinite Programming Relaxation [ J ]. IEEE Transactions on Antennas and Propagation,2012,60 (5): 2562-2565.
The above document [2] is: gu T, zhang X, he Z, et al phase-Only Nulling for Uniform Linear Array via Kronecker Decomposition [ A ]. In:2021XXXIVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS) [ C ].2021, pp.1-4.
In summary, the phased array beam forming method for suppressing the interference among beams provided by the invention can achieve the average and rate performance similar to the mixed beam forming under the condition that only analog beam forming is used instead of digital beam forming, and has an effective suppressing effect on the interference among the beams of users. Meanwhile, when a single wave beam is designed in the radar system, the wave beam null design scheme provided by the invention has better performance compared with the prior method.
The present invention is not described in detail in the present application, and is well known to those skilled in the art.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.
Claims (4)
1. A phased array beamforming method for suppressing inter-beam interference, the method comprising the steps of:
step S1, aiming at a wireless system, constructing an optimization problem with the linear combination of the power of the minimized wave beam in the interference direction and the power of the wave beam in the central area of the main lobe as an optimization target; the wireless system comprises a millimeter wave multiuser wireless communication system and a radar system, and the optimization problem satisfies the constant mode constraint of all phase shifters in the phased array;
step S2, designing a single beam or a plurality of beams for the wireless system by solving the optimization problem constructed in the step S1;
in the step S1, when the wireless system is a millimeter wave multi-user wireless communication system, firstly, constructing a downlink signal transmission model thereof, and constructing an optimization problem by taking a linear combination of the power of a current user beam in a main lobe central area thereof and the power of the beam in main lobe central areas of other user beams as an optimization target;
the downlink signal transmission model specifically comprises the following steps:
wherein y is q A signal representing the user's receipt;representing the downlink channel vector between the base station and the qth user, for example>Representing the complex field, (. Cndot. H Representing a conjugate transpose operation; />K column vectors +.>A beamforming vector representing the transmission of the base station to K users; />Representing the data streams sent by the base station to K users, which satisfy +.>Power constraint, P s The q-th element s representing the transmission power of the base station s] q Data representing the transmission of the base station to the qth user; η (eta) q Representing the additive white noise received by the qth user, subject to a mean of 0 and a variance of sigma 2 Complex gaussian distribution of (a);
in the downlink signal transmission model, the channel modeling is as follows:
wherein N is t Indicating the number of base station antennas L q Representing the total number of multipaths, alpha, of the channel between the base station and the qth user q,l And phi q,l The complex gain and departure angle of the first path of the q-th user are respectively represented; a (phi) q,l ) An array steering vector representing the first path of the qth user, the specific expression of which is:
wherein lambda is c For carrier wavelength, d represents the antenna element spacing, (·) T Representing a transpose operation;
the optimization problem is specifically expressed as:
wherein λ is a positive real weight factor, θ k,j A J-th sampling point, k=1, 2, …, K, j=1, 2, …, J, representing the central region of the main lobe of the kth beam; w (w) q Represents F RF Is the q-th column of (2);the power sum of the sampling points of the q-th beam in the central area of the main lobe of other beams is defined as the interference power sum of the q-th beam to the other beams; m represents the number of sampling points in the center region of the main lobe of the qth beam, +.>Representing the sum of the power of the M sampling points of the qth beam in the central region of its main lobeAnd; i·| represents modulo value, [ w ] q ] n Representing beamforming vector w q According to the constant modulus constraint of all phase shifters of the phased array, w q Each element of (a) satisfies
When the wireless system is a radar system, constructing an optimization problem for an optimization target by using a linear combination of the power of the minimum beam in the central area of a main lobe of the wireless system and the power of the beam in an interference area;
when the wireless system is a radar system, the optimization problem is specifically expressed as:
wherein λ is a positive real weight factor, w represents a beamforming vector, θ i,j The J-th sample point at the I-th interference region, i=1, 2, …, I, j=1, 2, …, J;representing the sum of the powers of the beams at the sampling points of the interference area; m represents the number of sampling points in the central region of the main lobe of the beam,/->Representing the sum of the powers of the M sampling points of the beam in the central region of the main lobe of the beam; [ w ]] n An nth element representing a beamforming vector w, each element in w satisfying +.>
2. The phased array beamforming method according to claim 1, wherein in said step S1, if the base station can obtain an accurate departure angle for each user, the main lobe center area is reduced to a center point.
3. The phased array beamforming method for suppressing interference between beams according to claim 1, wherein when the base station can obtain an accurate departure angle of each user, the main lobe central area is simplified to a central point, the corresponding optimization problem is specifically expressed as:
wherein θ k Representing the main lobe center point of the kth beam.
4. A phased array beamforming method for suppressing inter-beam interference according to any of claims 1-3, wherein in said step S2, the optimization problem is solved by a manifold optimization tool box.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210381030.6A CN114759959B (en) | 2022-04-12 | 2022-04-12 | Phased array beam forming method for inhibiting interference between beams |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210381030.6A CN114759959B (en) | 2022-04-12 | 2022-04-12 | Phased array beam forming method for inhibiting interference between beams |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114759959A CN114759959A (en) | 2022-07-15 |
| CN114759959B true CN114759959B (en) | 2024-01-30 |
Family
ID=82329088
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210381030.6A Active CN114759959B (en) | 2022-04-12 | 2022-04-12 | Phased array beam forming method for inhibiting interference between beams |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114759959B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116015375A (en) * | 2022-12-12 | 2023-04-25 | 东南大学 | Millimeter wave array communication multi-user beam tracking method based on auxiliary beam |
| CN118054825B (en) * | 2024-02-21 | 2024-10-18 | 浙江大学 | All-antenna multi-arm wave beam design method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018094565A1 (en) * | 2016-11-22 | 2018-05-31 | 深圳大学 | Method and device for beamforming under pulse noise |
| CN110365388A (en) * | 2019-07-31 | 2019-10-22 | 东南大学 | A kind of low complex degree millimeter wave multicast beam-forming method |
| CN110988816A (en) * | 2019-11-12 | 2020-04-10 | 西安电子科技大学 | Coherent MIMO radar transmitting waveform design method based on space-time phase coding |
| CN113721198A (en) * | 2021-09-09 | 2021-11-30 | 哈尔滨工程大学 | Physical layer security combined beam forming method for dual-function MIMO radar communication system |
-
2022
- 2022-04-12 CN CN202210381030.6A patent/CN114759959B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018094565A1 (en) * | 2016-11-22 | 2018-05-31 | 深圳大学 | Method and device for beamforming under pulse noise |
| CN110365388A (en) * | 2019-07-31 | 2019-10-22 | 东南大学 | A kind of low complex degree millimeter wave multicast beam-forming method |
| CN110988816A (en) * | 2019-11-12 | 2020-04-10 | 西安电子科技大学 | Coherent MIMO radar transmitting waveform design method based on space-time phase coding |
| CN113721198A (en) * | 2021-09-09 | 2021-11-30 | 哈尔滨工程大学 | Physical layer security combined beam forming method for dual-function MIMO radar communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114759959A (en) | 2022-07-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | Holographic integrated sensing and communication | |
| Han et al. | Hybrid beamforming for terahertz wireless communications: Challenges, architectures, and open problems | |
| Lu et al. | A tutorial on near-field XL-MIMO communications towards 6G | |
| CN114759959B (en) | Phased array beam forming method for inhibiting interference between beams | |
| Li et al. | Beyond diagonal reconfigurable intelligent surfaces: A multi-sector mode enabling highly directional full-space wireless coverage | |
| Liu et al. | Intelligent reflecting surface aided NOMA for millimeter-wave massive MIMO with lens antenna array | |
| CN113075622A (en) | Transmitting beam forming method for multi-user communication in radar communication integration | |
| Liu et al. | Multi-beam NOMA for millimeter-wave massive MIMO with lens antenna array | |
| Chen et al. | Simultaneous beam training and target sensing in ISAC systems with RIS | |
| Zhang et al. | RIS-aided 6G communication system with accurate traceable user mobility | |
| Yue et al. | Analysis of intelligent reflecting surface-assisted mmWave doubly massive-MIMO communications | |
| CN116633397B (en) | Array topology optimization method and device for AP subarrays of distributed MIMO system | |
| CN117375683A (en) | Communication-centric RIS-assisted non-cellular ISAC network joint beam forming method | |
| CN117459948A (en) | Reconfigurable intelligent surface position deployment method for general sense integrated system | |
| CN113595604B (en) | Multi-user millimeter wave communication beam forming method under partial connection architecture | |
| CN116614161A (en) | Radar communication integrated beam forming method based on linear constraint power distribution | |
| CN113992254B (en) | Intelligent reflecting surface assisted wireless communication system beam forming method | |
| Pan et al. | Downlink multi-user algorithms for millimeter-wave wideband linear arrays on PD-NOMA-based squint steering beams | |
| CN112636800B (en) | Mixed pre-coding method based on millimeter wave large-scale MIMO multi-user scene | |
| Meng et al. | Cooperative user-scheduling and resource allocation optimization for intelligent reflecting surface enhanced LEO satellite communication | |
| Saranya | Hybrid Digital Beamforming Design for Massive planar antenna array for 5G communication | |
| Kumaran et al. | Analysis on Hybrid Beamforming for 5G Energy Efficient Communications | |
| Kumar et al. | 2D active antenna array design for mMIMO to improve spectral and energy efficiency | |
| CN115334521B (en) | Partition base station design and three-dimensional coverage method based on intelligent reflecting surface | |
| CN114338311B (en) | Direction modulation method based on independent optimization of wave control beam and interference beam |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |